A Tablix data region displays data from a dataset. You can view all the data retrieved for the dataset or you can create filters so that you see only a subset of the data. You can also add conditional expressions to fill in null values or modify the query for a dataset to include columns that define the sort order for an existing column.

If you do want to handle null values differently, you can use conditional expressions or custom code to substitute a custom value for the null value. For example, the following expression substitutes the text Null wherever a null value occurs in the field [Size].

For more information about eliminating nulls in your data before retrieving the data from a SQL Server data source using Transact-SQL queries, see "Null Values" and "Null Values and Joins" in the SQL Server 2008 documentation in SQL Server Books Online.

By default, you can alphabetically sort values in a dataset field. To sort in a different order, you can add a new column to your dataset that defines the sort order you want in a data region. For example, to sort on the field [Color] and sort white and black items first, you can add a column [ColorSortOrder], shown in the following query: